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61.
62.
Jacob J. Burke 《Natural resources forum》1994,18(3):181-192
In southern Africa institutional capacity in the water sector is severely limited by diminishing regular budget and external assistance allocations. The result has been an overall decline in operational water resource management. This is ironic given the international community's current concern with 'integrated' or 'comprehensive' water resources management. Often, so-called integrated attempts at river basin planning and development have been conceived within the framework of a river basin authority or regional master plans. Such large-scale attempts have not necessarily been compatible either with the national capacity in water resources management or the existing institutional and legislative frameworks. In many cases the actual integration of a basin's physical resources and social, economic and environmental demands is poorly executed. To examine a way forward in resolving what is clearly an unsustainable state of affairs, a diagnostic study of the Kafue Basin, Zambia, was carried out in order to identify a set of water resource management options for a basin currently under stress. A physical framework for the Kafue Basin was established and principal subcatchments and hydro-geological subsystems identified. Current water resource issues in the basin are discussed and a multiobjective approach is proposed to allow intersectoral competition for the basin's limited water resources to be reconciled. 相似文献
63.
A case of combined partial mole and neural tube defect is presented. The detection of high levels of both maternal serum (MS) alpha-fetoprotein (AFP) and human chorionic gonadotrophin (hCG) during the second trimester led to the ultrasonic demonstration of anencephaly, omphalocele, and partial mole. This is the first report of combined elevation of MSAFP and MShCG. 相似文献
64.
Understanding resource-based communities (RBCs) as potential casualties of Canada's economic proclivity towards resource extraction projects may help us to generate political support for these communities at both local and national scales. The media has a critical role to play in promoting the development of this type of political discourse. This study examines how traditional print media coverage affects Canadians' perceptions of the Athabasca oil sands. A quantitative media analysis examines scope and thematic content of articles appearing in major Canadian newspapers between 2003 and 2013. We find that most coverage concerning the Athabasca oil sands over this period appears predominantly in western Canadian newspapers, with coverage primarily focusing on specific events. We argue that this geographic disparity in coverage does not provide Canadians with the adequate coverage necessary to develop an informed opinion on what the implications of ongoing oil sands development are at both a local and a national scale. 相似文献
65.
Jeffrey R. Brook Leiming Zhang Franco Di-Giovanni Jacob Padro 《Atmospheric environment (Oxford, England : 1994)》1999,33(30):1
This paper describes the development of a detailed dry deposition model for routine computation of dry deposition velocities of SO2, O3, HNO3 and fine particle SO42− across much of North America. Four different dry deposition/surface exchange sub-models have been combined with the current Canadian weather forecast model (Global Environmental Multiscale model) with a 3 h time resolution and a horizontal spatial resolution of 35 km. The present model uses the US Geological Survey North American Land Cover Characteristics data to obtain fourteen different land use and five seasonal categories. The four sub-models used are a multi-layer model for gaseous species over taller canopy land-use types, a big-leaf model for gaseous species over lower canopies (including bare soil and water) and for HNO3 under all surface types and, two different models for SO42−, one for tall canopies and the other for short canopies. All necessary parameters for each sub-model, chemical species, land-use and seasonal categories have been selected from available data libraries or from the values reported in the literature. The purpose for developing this model (referred to as the Routine Deposition Model (RDM)), when coupled with air concentration data, is to provide estimates of seasonal dry deposition, which can be combined with wet deposition to produce total deposition estimates. Model theory is discussed in this paper and model sensitivity tests and results will be presented in a companion paper. 相似文献
66.
Jacob A. Canick Glenn E. Palomaki Edward M. Kloza Geralyn M. Lambert-Messerlian James E. Haddow 《黑龙江环境通报》2013,33(7):667-674
Maternal plasma contains circulating cell-free DNA fragments originating from both the mother and the placenta. The proportion derived from the placenta is known as the fetal fraction. When measured between 10 and 20 gestational weeks, the average fetal fraction in the maternal plasma is 10% to 15% but can range from under 3% to over 30%. Screening performance using next-generation sequencing of circulating cell-free DNA is better with increasing fetal fraction and, generally, samples whose values are less than 3% or 4% are unsuitable. Three examples of the clinical impact of fetal fraction are discussed. First, the distribution of test results for Down syndrome pregnancies improves as fetal fraction increases, and this can be exploited in reporting patient results. Second, the strongest factor associated with fetal fraction is maternal weight; the false negative rate and rate of low fetal fractions are highest for women with high maternal weights. Third, in a mosaic, the degree of mosaicism will impact the performance of the test because it will reduce the effective fetal fraction. By understanding these aspects of the role of fetal fraction in maternal plasma DNA testing for aneuploidy, we can better appreciate the power and the limitations of this impressive new methodology. © 2013 John Wiley & Sons, Ltd. 相似文献
67.
Ammini Parvathi Vijayan Jasna Keshavan C. Haridevi Sebastian Jina Murali Greeshma Jacob Breezy Maheswari Nair 《Environmental monitoring and assessment》2013,185(10):8077-8088
Microbes play a central role in the decomposition and remineralization of organic matter and recycling of nutrients in aquatic environments. In this study, we examined the influence of physical, chemical, and biological parameters on the rate of bacterial production (BP) and viral production (VP) with respect to primary production over a diurnal period in Cochin estuary. Time series measurements were made every 2 h for 12 h (6 a.m.–6 p.m.) during periods of low and high salinities. The light intensity as photosynthetically active radiation, temperature, salinity, nutrients like NO3–N, SiO4–Si, and PO4–P, and chlorophyll a (Chl a) were measured along with BP, VP, and net primary production (NPP). NPP showed a strong positive correlation with light and Chl a (r 2?=?0.56 and 0.47, respectively), while VP showed a strong positive correlation with light, salinity, and Chl a (r 2?=?0.37, 0.58, and 0.37, respectively) and a negative correlation with BP (r 2?=??0.39) at P?≤?0.05. We observed a diurnal pattern in BP but did not have any significant correlation with light. Similar diurnal pattern was seen in VP, the peak of which was in succession with BP, suggesting that virus-mediated lysis plays an important role in loss processes of bacteria in Cochin estuary. The results of our study highlight the light-dependent and physicochemical-dependent diurnal variation in virioplankton production in a tropical estuarine ecosystem. 相似文献
68.
Gupta I Dhage S Jacob N Navada SV Kumar R 《Environmental monitoring and assessment》2006,114(1-3):199-209
The city of Mumbai, India with a population of 15 million discharges about 2225 MLD of domestic wastewater after partial treatment to adjoining marine water body. Under the Mumbai Sewage Disposal Project Scheme, sewage is being disposed to the west coast at Worli and Bandra through 3.4 kms long submarine outfalls. A field study was conducted at recently commissioned outfall diffuser location at Worli, at the onset of neap flood tide to study the dispersion patterns and measure the far field dilutions using radio and dye tracers. Estimated dilutions using different tracers were compared with outputs from an empirical model (Brooks) and a 2D numerical model (DIVAST). Validation using parameters such as BOD and FC, indicated a good match for BOD in near field compared to FC. The radiotracer 82Br and Rhodamine WT generally gave good correlation with Brooks' and DIVAST models for nearfield, however at further distances predictions were not accurate. 相似文献
69.
Samy S Zielinska B Sagebiel JC McDonald JD 《Journal of the Air & Waste Management Association (1995)》2011,61(3):319-323
To conduct low oxides of nitrogen (NOx) chamber experiments with modern diesel emissions (DE), a high-capacity NO, denuder was developed and used at the European Photoreactor (EUPHORE) outdoor simulation chamber. The denuder displayed a sufficient NOx storage capacity for use with DE, and efficient removal of NO, during injections of DE was achieved (>98%). Degradation of the denuder performance after repeated regeneration by heating (400 degrees C) and flushing with an air/oxygen ratio of 2:1 was not observed for a total of nine experiments. Evaluation of dark (with chamber cover closed) experiments (four in total) with and without the denuder in-line revealed some reduction (22%) of diesel particulate matter (DPM) with use of the denuder, most likely a result of impaction or settling of DPM during DE transit. However, DPM reduction may have also been a result of reductions in effective load of the engine-dyno system during the DE injections. Extensive chemical characterization of DPM revealed no significant perturbation of major compound groups associated with denuder use, except for nitrated polyaromatic hydrocarbon (NPAH) concentrations. The implications of high-NOx experiments without the use of a NOx denuder are discussed. 相似文献
70.
Jacob A. Benfield Paul A. BellLucy J. Troup Nicholas C. Soderstrom 《Journal of environmental psychology》2010
National parks have mandates both to preserve and protect natural settings and to assist visitors in viewing and interacting with those settings. Considerable scholarship has examined the trade-offs between preservation and recreation goals, such as protection of a natural setting when some visitors want to experience it from noisy aircraft or ground vehicles. The current project expands on previous noise research that showed the presence of aircraft noise to be detrimental to aesthetic and affective environmental assessments. Participants rated 25 scenes under quiet conditions or while hearing 45 dB(A) or 60 dB(A) of either natural sounds (bird calls, breeze through foliage), natural sounds with aircraft sounds, natural sounds with ground traffic sounds, or natural sounds with human voices. Results indicated that the presence of any anthropogenic noise–air traffic, ground traffic, or voices–negatively impacted environmental assessments, and more so at louder levels, while the natural soundscape had little to no effect on assessments. Additionally, the presence of air traffic, ground traffic, and human voices significantly decreased participant ratings of serenity while also increasing ratings of hostility. These effects were strongest for scenes that were high in scenic beauty. Results are discussed in the context of sound quality management in national parks and other settings. 相似文献